small bug fix in interval_arithmetic
small bug fix in interval_arithmetic

Davidjohnwilson/sympy,Sumith1896/sympy,lindsayad/sympy,shikil/sympy,kaushik94/sympy,asm666/sympy,Arafatk/sympy,jerli/sympy,AunShiLord/sympy,oliverlee/sympy,sunny94/temp,sunny94/temp,souravsingh/sympy,meghana1995/sympy,Davidjohnwilson/sympy,kevalds51/sympy,atsao72/sympy,wyom/sympy,postvakje/sympy,Gadal/sympy,beni55/sympy,mafiya69/sympy,lindsayad/sympy,Titan-C/sympy,emon10005/sympy,Curious72/sympy,maniteja123/sympy,atsao72/sympy,mcdaniel67/sympy,dqnykamp/sympy,Sumith1896/sympy,Gadal/sympy,AunShiLord/sympy,yukoba/sympy,MridulS/sympy,cccfran/sympy,drufat/sympy,amitjamadagni/sympy,rahuldan/sympy,Mitchkoens/sympy,emon10005/sympy,yashsharan/sympy,aktech/sympy,diofant/diofant,moble/sympy,shikil/sympy,garvitr/sympy,liangjiaxing/sympy,beni55/sympy,rahuldan/sympy,jamesblunt/sympy,kaichogami/sympy,mcdaniel67/sympy,kevalds51/sympy,farhaanbukhsh/sympy,jaimahajan1997/sympy,Designist/sympy,bukzor/sympy,jbbskinny/sympy,postvakje/sympy,toolforger/sympy,shipci/sympy,jbbskinny/sympy,liangjiaxing/sympy,abhiii5459/sympy,skidzo/sympy,emon10005/sympy,Vishluck/sympy,jamesblunt/sympy,Davidjohnwilson/sympy,kumarkrishna/sympy,sahmed95/sympy,asm666/sympy,pbrady/sympy,liangjiaxing/sympy,sampadsaha5/sympy,pandeyadarsh/sympy,aktech/sympy,kaichogami/sympy,cswiercz/sympy,kumarkrishna/sympy,cccfran/sympy,drufat/sympy,skidzo/sympy,chaffra/sympy,hrashk/sympy,atreyv/sympy,yukoba/sympy,Sumith1896/sympy,Curious72/sympy,jamesblunt/sympy,Curious72/sympy,ahhda/sympy,moble/sympy,sahmed95/sympy,sahmed95/sympy,hrashk/sympy,jerli/sympy,kumarkrishna/sympy,ChristinaZografou/sympy,grevutiu-gabriel/sympy,grevutiu-gabriel/sympy,sampadsaha5/sympy,ahhda/sympy,madan96/sympy,sahilshekhawat/sympy,iamutkarshtiwari/sympy,ChristinaZografou/sympy,AunShiLord/sympy,yashsharan/sympy,moble/sympy,MridulS/sympy,Mitchkoens/sympy,Mitchkoens/sympy,cccfran/sympy,shipci/sympy,Vishluck/sympy,oliverlee/sympy,AkademieOlympia/sympy,wyom/sympy,ahhda/sympy,rahuldan/sympy,drufat/sympy,vipulroxx/sympy,ga7g08/sympy,sahilshekhawat/sympy,mafiya69/sympy,meghana1995/sympy,kaushik94/sympy,Gadal/sympy,toolforger/sympy,chaffra/sympy,Arafatk/sympy,flacjacket/sympy,kevalds51/sympy,maniteja123/sympy,hargup/sympy,ga7g08/sympy,bukzor/sympy,madan96/sympy,vipulroxx/sympy,garvitr/sympy,debugger22/sympy,souravsingh/sympy,atreyv/sympy,bukzor/sympy,Arafatk/sympy,farhaanbukhsh/sympy,shikil/sympy,wanglongqi/sympy,debugger22/sympy,garvitr/sympy,maniteja123/sympy,asm666/sympy,Vishluck/sympy,jerli/sympy,wyom/sympy,souravsingh/sympy,saurabhjn76/sympy,srjoglekar246/sympy,oliverlee/sympy,mafiya69/sympy,hargup/sympy,Titan-C/sympy,amitjamadagni/sympy,sahilshekhawat/sympy,skidzo/sympy,pbrady/sympy,MechCoder/sympy,abloomston/sympy,cswiercz/sympy,pandeyadarsh/sympy,wanglongqi/sympy,abloomston/sympy,meghana1995/sympy,yashsharan/sympy,saurabhjn76/sympy,iamutkarshtiwari/sympy,AkademieOlympia/sympy,VaibhavAgarwalVA/sympy,abhiii5459/sympy,yukoba/sympy,MechCoder/sympy,jbbskinny/sympy,Designist/sympy,jaimahajan1997/sympy,saurabhjn76/sympy,MechCoder/sympy,lidavidm/sympy,dqnykamp/sympy,vipulroxx/sympy,ChristinaZografou/sympy,abloomston/sympy,beni55/sympy,kmacinnis/sympy,shipci/sympy,kaushik94/sympy,MridulS/sympy,Shaswat27/sympy,skirpichev/omg,dqnykamp/sympy,postvakje/sympy,pandeyadarsh/sympy,Shaswat27/sympy,cswiercz/sympy,lidavidm/sympy,madan96/sympy,Titan-C/sympy,debugger22/sympy,toolforger/sympy,kaichogami/sympy,Designist/sympy,lidavidm/sympy,jaimahajan1997/sympy,sampadsaha5/sympy,wanglongqi/sympy,farhaanbukhsh/sympy,VaibhavAgarwalVA/sympy,aktech/sympy,mcdaniel67/sympy,kmacinnis/sympy,iamutkarshtiwari/sympy,kmacinnis/sympy,abhiii5459/sympy,Shaswat27/sympy,hrashk/sympy,atsao72/sympy,ga7g08/sympy,sunny94/temp,AkademieOlympia/sympy,lindsayad/sympy,chaffra/sympy,grevutiu-gabriel/sympy,atreyv/sympy,pbrady/sympy,hargup/sympy,VaibhavAgarwalVA/sympy